package com.dajinling.socket.server;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.stereotype.Component;

import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicInteger;

@ServerEndpoint("/websocket/{sid}")
@Component
public class WebSocketServer {

    //静态变量，用来记录当前在线连接数。应该把它设计成线程安全的。
    private static AtomicInteger onlineNum = new AtomicInteger();

    //concurrent包的线程安全Set，用来存放每个客户端对应的WebSocketServer对象。
    private static ConcurrentHashMap<String, Session> sessionPools = new ConcurrentHashMap<>();


    /**
     * 发送消息
     * @param session
     * @param message
     * @throws IOException
     */
    public void sendMessage(Session session, String message) throws IOException {
        if (session != null) {
            synchronized (session) {
                session.getBasicRemote().sendText(message);
            }
        }
    }


    /**
     * 给指定用户发送信息
     * @param userName
     * @param message
     */
    public void sendInfo(String userName, String message) {
        Session session = sessionPools.get(userName);
        try {
            sendMessage(session, message);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 给所有用户发送信息
     * @param message
     */
    public void sendAll(String message) {
        try {
            for(Map.Entry<String, Session> entry: sessionPools.entrySet()) {
                sendMessage(entry.getValue(), message);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 建立连接成功调用
     * @param session
     * @param userName
     */
    @OnOpen
    public void onOpen(Session session, @PathParam(value = "sid") String userName) {
        //存入用户以及他对应的session
        sessionPools.put(userName, session);

        addOnlineCount();

        System.out.println(userName + "加入webSocket！当前人数为" + onlineNum);

        try {
            sendMessage(session, "欢迎" + userName + "加入连接！");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


    /**
     * 关闭连接时调用
     * @param userName
     */
    @OnClose
    public void onClose(@PathParam(value = "sid") String userName) {
        //从集合中删除该用户
        sessionPools.remove(userName);

        subOnlineCount();

        System.out.println(userName + "断开webSocket连接！当前人数为" + onlineNum);
    }


    /**
     * 收到客户端信息
     * @param message
     * @throws IOException
     */
    @OnMessage
    public void onMessage(String message) throws IOException {
        ObjectMapper om = new ObjectMapper();

        Map<String, String> map = om.readValue(message, new TypeReference<Map<String, String>>() {
        });

        Session session = sessionPools.get(map.get("toUserId"));
        if (session != null) {
            try {
                sendMessage(session, map.get("sendMsg"));
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    //错误时调用
    @OnError
    public void onError(Session session, Throwable throwable) {
        System.out.println("发生错误");
        throwable.printStackTrace();
    }

    //增加一个连接
    public static void addOnlineCount() {
        onlineNum.incrementAndGet();
    }

    //减少一个连接
    public static void subOnlineCount() {
        onlineNum.decrementAndGet();
    }
}
